It is no secret in Iran: Authorities have gone out of their way to publicize a crackdown against thugs and smugglers that has also enveloped academics and women whose dress is deemed "un-Islamic."

Masked police dressed like black-clad storm-troopers have been arresting, humiliating, and parading criminals. Cameras follow cops on nighttime raids against drug dealers that net hundreds in a single night.

But analysts say that what appeared to be just another cleanup when it began last spring is proving to be a strategic effort to protect the regime from "vulnerabilities" that could be exploited by archenemies such as the United States. Picking up criminals and intimidating all potential opponents of clerical rule, they say, aims to prevent a repeat of history by preempting violence that could spin out of control.

"The girls are not the target," says an Iranian journalist, noting that many women still deliberately flout the rules. "The core reason is dealing harshly with thugs. Now they are preempting – they are keeping a potential threat from growing," says the journalist. "They are looking at modern history [and] going onto the Internet."

That history shows how the CIA in 1953 staged a coup against Iran's popular Prime Minister Mohammad Mossadeq. A crucial factor in its success were mobs organized by CIA-paid agents to rampage and take over the streets; others soon joined the rioters.

And on the Internet, Iran's security services have become familiar with American regime-change neoconservatives such as Michael Ledeen, who has argued that with US support, "we could liberate Iran in less than a year."

The Iranian journalist paraphrases those ideas – and the threat perceived from them – this way: "In the war with Iran, the US will not be the foot soldiers," but will "just provide the trigger" for Iranians to rise and topple the government.

In Iran, anticriminal measures against those called "knife-pullers" in Farsi are widely lauded. Iran's supreme religious leader, Ayatollah Sayyed Ali Khamenei, has told police that they "must strongly continue with the 'social security plan' … so that its goals are institutionalized in society."

But in one of the most far-reaching drives since the 1979 Islamic revolution, enforcement has spread far beyond criminal offenders to young women showing too much hair and Western-educated academics accused of being "agents" for US-inspired regime change.

This past weekend, 24 Internet cafes and coffeehouses were shut down in a sweep of 435 such locales, Reuters reported. Police said they were shut for "using immoral computer games [and] storing obscene photos." A fresh "winter" crackdown was announced last week on un-Islamic dress, which includes women's high boots.

"Their vulnerable spot is these 'Westoxicated' Iranians – the threat is not military attack, but Iranians who 'live differently from us,' who listen to the West," says a veteran analyst who asked not to be named. "Many would follow those [thugs] who are willing to attack."

Iran's new Revolutionary Guard commander, Mohammad Ali Jafari, said in late September that the "main responsibility" of his forces is to counter "internal threats." One vigilante newspaper has railed against the risks of "freedom."

The morality enforcement is a reversal in some ways. For years, conventional wisdom held that conservatives would not risk a serious social crackdown, fearing a popular backlash that could threaten their grip on power. But women and labor activists have been arrested as well as students who have staged protests against the president and government policies in the past year. Three who have been in prison for eight months – their fate sparking a number of demonstrations – are to be released Saturday, acquitted of "insulting religious values" and other charges.

Amnesty International notes that the number of executions has risen from 177 in 2006 to more than 210 so far this year. The UN General Assembly Tuesday approved a draft resolution noting "very serious concern" with human rights violations in Iran, including cases of "torture and cruel, inhuman or degrading treatment or punishment, including flogging and amputations."

The steps being taken hark back to the earliest years of the revolution, when "securing the system" was deemed the highest obligation, like prayer. Experts note, however, that unlike in both 1979 and 1953, the regime now has many loyal security forces and vigilante groups whose job is to protect the system and ensure, in the words of one Farsi slogan often applied by critics, "victory through creating fear."

"The US planned two wars against us, a hard war and a soft war," says Hojjatoleslam Seyyed Abolhasan Navvab, an influential cleric. "The hard war, it is only intimidation and slogans. But the soft war, it goes more toward reality [by provoking] social, cultural, ethnic, and religious conflicts."

"It is not a flood, but this is a very slight rain that is continuous, and when it washes away it has a ruinous effect," says Mr. Navvab. "If you take it seriously, the level of danger drops. If you don't take it seriously, the danger is there and it is firm."

Noting the months-long arrests of several dual US-Iran citizens earlier this year, Navvab charged that some academics "turned out to be agents of foreigners." The impact of such beliefs has been widely felt.

"I have never seen Iran like this in 28 years," says one political analyst, who has been warned about contact with Westerners. "Early in the revolution, there was mass jubilation, and repression was very targeted against [armed opposition]. If you were not a member, you had no reason to fear. Now it's a systematic intimidation, and they are very good at it."

US expenditures of $75 million on "pro-democracy" efforts, most of it on broadcasts into Iran from outside, has helped provide a pretext. "The whole security environment is intended to really suffocate or torpedo any possible change from within. They believe this mass conspiracy [of regime change]," says the analyst. The result is a "sense of fear, and making engagement in politics at any level a high-risk endeavor."

Last week, parliamentarians angry about the book crackdown called for moderation. "A Muslim woman wearing high boots with a coat and other coverings does not contradict Islam," said Mohammad Taghi Rahbar, a member of parliament and cleric who was quoted in the Iranian press, according to Agence France-Presse.

One focus has been "Westoxicated" youths, and women showing too much hair or wearing tight manteaus that by law must hide the shape of the body. Morality police park at malls and take photos for criminal files of "bad hijab" violators. Some women have been warned that a third infraction will cause banishment from Tehran.

Presidential aide Mehdi Kalhor, who famously called for much greater social openness in 2005, has also asked for limits on police zeal. "I wrote a letter to the head of law enforcement and asked him to refrain from extremism, [to] execute the [minimum] level of the law," he said in an interview. "It's the right of each citizen to have an ordinary life, without being disturbed and agitated."

Iranian academics have received directives to halt all contacts with foreigners. Civil society efforts – even cultural events hosted by Western embassies in Tehran have dried up, since attendees were harassed, sometimes physically. "There is a genuine concern in the regime that we in the West would like the regime to change, and they are right, for some people," says a European diplomat. "Some think we are not going to do it with bombs and missiles, but through a velvet revolution."

That means special attention paid to civil-society activists. At a recent meeting to express solidarity with Emadedin Baghi, the founder of Society for Protecting Prisoners' Rights who was arrested in October, some spoke out. "A regime that can't respect such a soft-spoken, moderate person is a cause for concern," says Ezatollah Sahabi, a reformist editor who has done prison time. "No reformist wants to go beyond [limits] – just respect the rights of the citizens. We don't want to push the regime into a critical situation."